As this type of light-emitting sensor device, there is a device for applying light such as laser light to a living body and for calculating the blood flow velocity of the living body from a change in wavelength by Doppler shift in its reflection or scattering (e.g. refer to patent documents 1 to 3).
On the other hand, for example, in a patent document 4, there is suggested a technology in which measurement accuracy is increased by providing a light scatterer on light incoming side and outgoing side with respect to body tissue on a device for measuring the concentration of a light absorbing material in the body tissue by using a pulse photometry technology.    Patent document 1: Japanese Patent Application Laid Open No. 2004-357784    Patent document 2: Japanese Patent Application Laid Open No. 2004-229920    Patent document 3: Japanese Patent Application Laid Open No. 2006-130208    Patent document 4: Japanese Patent Application Laid Open No. 2001-198111